1. Field of the Invention
One or more embodiments of the present invention relate to an organic light-emitting display device and a method of manufacturing the same.
2. Description of the Related Art
As the information society has been developed, various types of display devices are required, and flat panel display devices, such as liquid crystal display (LCD) devices, organic electroluminescent display devices, plasma display panel (PDP) devices, field emission display devices, or the like, have been widely developed. Active matrix type flat panel display devices in which a plurality of pixels are arranged in the form of a matrix are mainly used. The pixel includes thin film transistors (TFTs) that are switching elements and drives the TFTs individually.
Each TFT includes an active layer formed of a semiconductor material, such as silicon. Hydrogenated amorphous silicon (a-Si:H) may be formed on a large substrate, such as a low-cost glass substrate, at a low temperature, and a process of forming amorphous silicon (a-Si:H) is simple and thus is widely used.
However, TFTs using hydrogenated amorphous silicon (a-Si:H) have low field effect mobility and low response speeds, and in particular, it is difficult to perform high-speed driving on TFTs using hydrogenated amorphous silicon (a-Si:H) on the large substrate.
Thus, display devices that employ TFTs using polycrystalline silicon, have been widely studied and developed. In display devices using polycrystalline silicon, TFTs in pixel areas and circuits for driving the TFTs may be formed on the same substrate, and a process of connecting TFTs in pixel areas and circuits for driving the TFTs is not required so that the entire process is simplified. In addition, polycrystalline silicon has relatively high field effect mobility that is 100 to 200 times than that of hydrogenated amorphous silicon (a-Si:H) and thus has high response speeds and has high stability with respect to temperature and light.
In addition, as display devices are gradually souped-up, strict management of device characteristics is required. The management of device characteristics is necessary for quality control, early discovery of a defective substrate, and prevention of process disclosure of the defective substrate.